To be specific. Most of my basement rainwater comes from my roof. We had a birds nest up there blocking the gutters. This caused the water to spill over and get into the basement. Once we fixed that no more water in the basement. Something to quickly check!

What follows is my understanding as a homeowner with potentially unpermitted work done in my house before we bought it. I don’t lose sleep over it, as it all meets code. The answers will vary a lot here, but work done without a permit may still meet code, but in order to verify that a lot of holes must be cut in the walls etc to verify the mechanicals (plumbing, electrical etc.) Even if you wanted to get it permitted you would need a licensed contractor who isn’t going to put their name on someone else’s work, so you’re left with ripping it all out to get it done “right”. The more interesting question is do you want to get your house reassessed/were photos posted online for assessors to glean data from. The tax assessors office does not, as far as I’m aware, report your self reporting of a different layout to city inspectors office, so you could call them and explain you want to update the records as you see it’s listed incorrectly. This will then bring the official records up to date and in the future it’s just “how it was”.

All in all, major improvements without any permits are not ideal, but by the time you are ready to sell it will all be water under the bridge. Last comment is though you will likely not get far it is interesting that the title company didn’t notice you had a 2br/2bath home now yet the records listed it as 3br/1bath. Again, I doubt you’ll have much of a case, but maybe a thread to pull.